Underwater propeller



FIG. 1 is a perspective view of an underwater propeller showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown on the drawings depict portions of the underwater propeller that form no part of the claimed design. 

CLAIM The ornamental design for an underwater propeller, as shown and described. 